MESOSCALE DISCUSSION 0446
   NWS STORM PREDICTION CENTER NORMAN OK
   0603 PM CDT SAT APR 11 2009
   
   AREAS AFFECTED...WRN INTO PARTS OF NW TX
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 139...
   
   VALID 112303Z - 120030Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 139
   CONTINUES.
   
   TRENDS WILL BE MONITORED FOR AN INCREASING SEVERE THREAT TO THE
   NORTHEAST OF WW 139.  A NEW WATCH COULD BECOME NECESSARY...OR
   ADDITIONAL COUNTIES ADDED TO THE CURRENT WATCH...BY 01-02Z.
   
   THE FIRST COUPLE IN A SERIES OF SMALLER SCALE IMPULSES EMANATING
   FROM THE BASE OF THE LARGE-SCALE UPPER TROUGH OVER THE PLATEAU
   REGION HAVE SUPPORTED ONGOING CONVECTIVE CLUSTERS ACROSS THE
   SOUTHERN HIGH PLAINS...FROM NEAR OR JUST NORTH OF THE DAVIS
   MOUNTAINS THROUGH THE TEXAS PANHANDLE AREA.  THESE FEATURES ARE
   PROGRESSING THROUGH DEEP LAYER SOUTHERLY FLOW TO THE EAST OF THE
   TROUGH...WITH THE STRONGEST IMPULSE APPARENTLY STILL DIGGING THROUGH
   THE NORTHWESTERN MEXICAN PLATEAU.  UNTIL THIS SYSTEM TURNS EASTWARD
   TOWARD SOUTHWEST TEXAS LATER THIS EVENING...CONVECTION IS EXPECTED
   TO TEND TO DEVELOP FASTER TO THE NORTH THAN EAST...ACROSS WEST
   TEXAS.
   
   STRONGEST STORMS THROUGH 00-01Z ARE EXPECTED TO REMAIN FOCUSED
   WITHIN A LINGERING LOW-LEVEL THERMAL RIDGE ACROSS THE PECOS VALLEY
   INTO THE MIDLAND/ODESSA AREA...AND PERHAPS WITHIN THE STRONG
   ELEVATED WARM ADVECTION REGIME ON THE EDGE OF THIS RIDGE...EAST OF
   HOBBS NM THROUGH AREAS NORTH OF MIDLAND/BIG SPRING.  DESPITE SIZABLE
   SURFACE TEMPERATURE/DEW POINT SPREADS...LARGE CLOCKWISE CURVED
   LOW-LEVEL HODOGRAPHS COULD BECOME SUPPORTIVE OF SIGNIFICANT
   LOW-LEVEL MESOCYCLONES...PERHAPS CAPABLE OF PRODUCING AN ISOLATED
   BRIEF TORNADO...IN ADDITION TO LOCALIZED DAMAGING WIND GUSTS...IN
   BOUNDARY LAYER BASED STORMS.  OTHERWISE...LARGE HAIL IS PROBABLY THE
   PRIMARY SEVERE THREAT IN THESE STORMS...AND ELEVATED STORMS TO THE
   NORTH...WHICH COULD BEGIN TO SPREAD EAST OF LUBBOCK TOWARD CHILDRESS
   PRIOR TO CURRENT WATCH EXPIRATION.
   
   ..KERR.. 04/11/2009
   
   
   ATTN...WFO...SJT...LUB...MAF...
   
   LAT...LON   32800282 33690256 34220139 33580072 32390095 31420165
               30530240 31050316 32800282